The present invention relates to an average pitot-tube type flow meter and, more particularly, to the average pitot-tube type flow meter that does not require straight run so that the degree of freedom for its installation is enhanced.
When an average pitot tube type flow meter is mounted on a pipe, the water flow in advance of and behind the average pitot-tube type flow meter should be stabilized so that straight runs are required in advance of and behind the average pitot-tube type flow meter.
If it is difficult to secure the straight run length, a rectifying device can be installed to reduce the straight run length.
The rectifying device has a multiple of tubes arranged in parallel one another and the section of the tube can have various shapes. Such a rectifying device is defined in ISO 516701 and so on.
As the fluid passes the plural tubes arranged in parallel one another in the rectifying device, the distribution of the velocity from the wall to the center in the pipe becomes uniform.
The rectifying device includes, for example, Zanker type, Sprenkie type, AMCA type and Etoile type.
However, even if the rectifying device is used, the straight run is still necessary. So, there remains the limit in the installation and inconvenience to install the rectifying device in advance of the pitot-tube type flow meter as well as to install the pitot-tube type flow meter.
Accordingly, a pitot-tube type flow meter is demanded that does not need the straight run so that it is possible to enhance the degree of freedom in the installation and that can eliminate the inconvenience to install the rectifying device separately.
Meanwhile, in the conventional pitot-tube type flow meter, the total pressure tube and the static pressure tube are integrated to one body and they are separated by the separation wall. For example, Korean patent No. 0201077 shows such a structure. However, there is a problem that it is not easy to manufacture the total pressure tube and the static tube integrated to one body.